Question:
First of all is it recommended to have Tracheal, Cloacal swab and tissue homogenize only or serum sample can be good for test? In the procedure you said add 200ul of samples to the sample preparaion reagents in the dilution tray. Here people are a bit confused according to the sample source, if it is swab how they can do it?, if it is serum it will be difficult to get 200 ul from Falcons (very important bird in the area)?. Is there is any sample treatment (specially swab or tissue homogenized prior to addition to the sample preparation reagnet in dilution tray? if yes what diluent they should use, please recommend.
Resolution:
- Serum samples are generally not the sample of choice for Flu antigen detection. We have tested 25-30 samples from a "non-endemic" area and got no false positives, but we have never tested any known positive serum samples. If the customer wants to test serum, and they don't have much volume, they could try 25 ul SPR + 100 ul sample, and still test 100 ul in the assay.
- Generally, swabs are placed in 1-2 ml of Viral Transport Medium (sterile, available commercially, same material used for human specimens that are destined for culture isolation). An alternative to VTM is Brain-Heart Infusion (BHI) medium. Another alternative is Hank's Balanced Salt Solution. Sometimes, when large scale screening is being done, 2-5 swabs(from different birds) are placed in 5 ml of medium. Generally, the swabs are triturated to express collected material into the medium, the swab handle is broken off, and the swab is left in the tube. Also, most of the media contain antibiotics of some sort.
- For tissue homogenates, VTM, HBSS, etc. is used to prepare a 10% (w/v) homogenate (sand, mortar/pestle) of the tissue of interest. The homogenized tissue is transferred to a tube and centrifuged. Samples are removed for virus isolation/antigen detection and the balance is stored frozen (to reduce/eliminate bacterial growth) for follow-up testing.
